[ovs-dev] [PATCH v1 11/14] netdev-dpdk: support multi-segment jumbo frames

Eelco Chaudron echaudro at redhat.com
Tue Jul 3 13:03:58 UTC 2018

On 28 Jun 2018, at 17:41, Tiago Lam wrote:

> From: Mark Kavanagh <mark.b.kavanagh at intel.com>
> Currently, jumbo frame support for OvS-DPDK is implemented by
> increasing the size of mbufs within a mempool, such that each mbuf
> within the pool is large enough to contain an entire jumbo frame of
> a user-defined size. Typically, for each user-defined MTU,
> 'requested_mtu', a new mempool is created, containing mbufs of size
> ~requested_mtu.
> With the multi-segment approach, a port uses a single mempool,
> (containing standard/default-sized mbufs of ~2k bytes), irrespective
> of the user-requested MTU value. To accommodate jumbo frames, mbufs
> are chained together, where each mbuf in the chain stores a portion of
> the jumbo frame. Each mbuf in the chain is termed a segment, hence the
> name.
> == Enabling multi-segment mbufs ==
> Multi-segment and single-segment mbufs are mutually exclusive, and the
> user must decide on which approach to adopt on init. The introduction
> of a new OVSDB field, 'dpdk-multi-seg-mbufs', facilitates this. This
> is a global boolean value, which determines how jumbo frames are
> represented across all DPDK ports. In the absence of a user-supplied
> value, 'dpdk-multi-seg-mbufs' defaults to false, i.e. multi-segment
> mbufs must be explicitly enabled / single-segment mbufs remain the
> default.
> Setting the field is identical to setting existing DPDK-specific OVSDB
> fields:
>     ovs-vsctl set Open_vSwitch . other_config:dpdk-init=true
>     ovs-vsctl set Open_vSwitch . other_config:dpdk-lcore-mask=0x10
>     ovs-vsctl set Open_vSwitch . other_config:dpdk-socket-mem=4096,0
> ==> ovs-vsctl set Open_vSwitch . other_config:dpdk-multi-seg-mbufs=true
> Co-authored-by: Tiago Lam <tiago.lam at intel.com>
> Signed-off-by: Mark Kavanagh <mark.b.kavanagh at intel.com>
> Signed-off-by: Tiago Lam <tiago.lam at intel.com>


Acked-by: Eelco Chaudron <echaudro at redhat.com>


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